Staff Answer
Sep 28, 2026 - 07:30 AM
"AC lo" means the board sees low AC voltage. If it's switching back and forth between AC and gas, the voltage is probably dropping when the heater kicks on. Measure AC at the fridge outlet while it's trying to run on AC. If it drops well below 110V, fix the supply (a loose connection or long extension cord). If the AC is solid and the board still won't send power to the heaters, the board is the cause. For 1200s with serials between 832172 and 8981138, that's the 621271001 power board or Dinosaur 6212XX.
If you have any questions, just reach out at info@rvfridgeguys.com or call us at 800-712-8822. You can find everything we carry at www.rvfridgeguys.com.
